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How Does Webasto Work for Hot Water?
Good Morning – still VERY new to the Prevost world (less than 90 days of ownership) and it now seems our electric hot water heater is no longer working as well as it did, so interested in supplementing hot water production by using the Webasto.
In our prior coach which had a dual fuel Oasis two-element electric / diesel water heater, it was easy to use and we often used its diesel function to have endless hot water by turning it on immediately prior to showering. During PDI, I tested the Webasto for cabin heat production only.
If I run the Webasto for supplemental hot water (with the cabin heat thermostats set to their lowest setting) how long in advance should I run the Webasto prior to needing supplemental hot water? Also, will running the Webasto for showering cause a rise in ambient cabin temperature even if the thermostats are not calling for cabin heat? (hot water or fluid running through the system?)
THANK YOU very much, Jeff
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11 Replies
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When you turn the webasto switch on it is then circulating the coolant throughout the system. So yes a rise in cabin temp will happen even with the inside t-stats off. I dont know a specific time however I would say 30 minutes prior would be plenty of time…
1999 XLV X-6872, liberty #440 -
That would not be adequate time on my setup…YMMV since it’s a 2007 but what’s wrong with the electric? Electric would heat in 30 minutes or so.
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Now that I have more time, I’ll dive deeper ASSUMING your system is like mine.
First, water heater will work electrically if you are running generator or plugged in and the water heater breaker is on.
Second, engine coolant is circulated to the water heater (approx 200F) to heat water while driving. Webasto functions similarly circulating coolant but only heats water to about 160F which is still plenty hot.
Here’s the rub; unless your name is Jon, if the water in your water heater reaches 200F, it will trip off an overheat safety switch on the water heater and the water heater will not work electrically until that switch is manually reset. In order to avoid this occurence if the coach is driven for extended intervals, most owners restrict the flow of coolant to the water heater by partially closing a gate valve over the water heater. While this will generally be about 97.5% effective, it also restricts the webasto’s ability to heat water quickly because the webasto uses the same plumbing. (Jon’s solution is more effective and much more elegant but I leave you to the search function)
It is for the above reason I say that the webasto will, if the flow has been restricted, take a while to heat your water. If the electric seemed to work fine, then you took a drive, and now not so hot, you may check the operation of the water heater in a couple ways. When the water is cold or cool and you have electricity, turn on breaker and look for about a 7 amp draw increase on your panel indicating the heating elements are on. If they are not, there is probably a small panel on the side of your water heater with a screw which, when removed, exposes the overtemp limit switch and a reset button, probably red in color.
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I will never want to rely on Webasto to only heat hot water. Depending on how valves are set it heats the entire coach, the engine or hot water heater but it is like using a shotgun to catch mice. Overkill.
If your electric supply to the Hw tank is not working it is highly probable it is either a burned out heater element or a failed thermostat. Both are relatively easy fixes and preferable to relying on the Webasto. With the internet and overnight delivery and the use of an electric tester prior to ordering the problem is easily diagnosed to be an open thermostat or open (failed) heating element.
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PS WARNING THIS MAY NOT BE NECESSARY, BUT REMOVING THE SIDE COVER TO THE OVERHEAT SWITCH WILL EXPOSE SOME WIRING. I WOULD TURN BREAKER OFF BEFORE REMOVING SMALL PANEL.
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Some converters, like Royale, that use Aqua-Hot, will have a significantly different system. While an Aqua-Hot system uses a Webasto burner, it normally does not have external electrical hot water heaters. The electrical heating element (s) is built in to the system. An Aqua-Hot system will provide continuous hot water using the diesel burner alone. It also does not run the circulating pumps to the interior heat exchangers until heat is called for. For dry camping and needed hot water, the Aqua-Hot system has the advantage.
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Thank you all for your replies! The electric water heater still works, yet does not seem to supply as much hot water as early on this our first adventure. And, I do not believe it is a case of the cold water supply being frigid. I will check to see if this unit has two elements as perhaps one is no longer working. Thank you!
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The unit has a single element and it is either working or not. During the summer heat the incoming fresh water is not likely to be frigid.
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Jeff, Aqua-Hot as mentioned above has no similarity to your Liberty system, so don’t let that confuse you. Les is trying to help, but apples to oranges. Your Webasto and electric water heater are independent of each other, but do share the engine coolant when using Webasto.
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Jeff: We have a 99 Liberty with a Raritan water heater, I suspect you probably have a similar device. If you do, let me share my experiences.
A number of years ago we couldn’t get any hot water using electric. So based on consultation with Jeff Rowe at ETLC I determined that the electric heating element was kaput. Using a 120volt AC trouble light I had power to the thermostat and power from the thermostat to the element. So the element had power, but apparently wasn’t heating the water.
After turning off the breaker for the water heater AND draining the water heater (Liberty thoughtfully provides valves for that as part of the winterization functionally built into their coaches) I carefully removed the element. Jeff warned me that it could be a little hard to get out because of calcium build-up, and it was.
Then it was off to the local ACE hardware store. There wasn’t an exact match, but it appeared most of the available elements had the same “thread-size” which is the most important aspect. Some were a little longer, some shorter, and there were modest variations in wattage and hence BTU values. As I understand the Raritan, its only a 120volt AC device. Your home electric water heater is a 240volt AC device and uses TWO of these 120volt AC heating elements to heat your hot water. That’s why the hardware store one works.
I actually picked one with a slightly higher amp drawn and wattage. But the water heater should be wired for 15 amps and should be on a 15 amp breaker and as long as the element we pick is under 80% of 15 (i.e. 12 amps or 1,440 watts) we should be OK. (I’m sure if my assumptions are incorrect the EE’s and Sparkys will correct me.)
I put it in, hooked up the wires, and it worked great. Hot water again!
Only problem is that its an awkward place to work. Someone with long arms should find it much easier than I did.
Then about a year or so later the water heater started to leak and Jeff’s crew replaced it with a brand new one.
Then on our 100 day trip this past winter we didn’t again have hot water. Checked with Jeff, water heater fairly new, should be OK. He said there is a switch or breaker on the water heater that might have tripped, try that first. Its under the plastic cover. So I turned the water heater breaker off, took the cover off, pushed the button, and was pretty sure I heard a “click”. Flipped the breaker back on and saw an immediate draw on the amperage readout, so I figured out the water heater was working. In about 30 minutes the water was hot. Turned the breaker off, put the cover back on, turned the breaker off, and have had hot water ever since.
Next time I saw Jeff I thanked him for that advice. He said some owners will drill a hole in the plastic cover right over the button with a step drill so they can easily reset the button on the overload switch without removing the plastic cover which was difficult to remove and get back on in my case.
Hope all this helps!
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Keep in mind Jeff is getting hot water, just not as fast as he feels he should.
A greater wattage element will help, but the current draw cannot exceed the circuit breaker or safety device limits or what the wires are rated to carry.
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